1. Field of the Invention
The present invention relates to a method of cleaning a container, such as a can for containing a resist, and a cleaning apparatus for carrying out the method.
2. Description of the Related Art
A resist to be applied to LCD substrates is delivered to the user in a can called a NOWPAK (trade name). A pack of a resist is prepared by filling a container lined with a liner, and attaching a cap, a closure and a dip tube to the container. The pack of the resist is delivered from a production company to a user. After the resist contained in the container has been consumed, the pack is returned from the user to the production company. The production company extracts the liner from the empty container, disposes of the extracted liner, cleans the container, the cap, the closure and the dip tube, lines the cleaned container with a new liner, fills up the container with the resist, attaches the cap, the closure and the dip tube to the container to complete a pack, and then sends the pack containing the resist to the user.
A conventional method of cleaning the used container to reuse the same comprises the steps of cleaning the container with a solvent by hand, rinsing the container with water, and drying the container. A solvent, such as acetone, methyl ethyl ketone or an alcohol, is used for solvent cleaning. Such a solvent, however, has a low flash point and a danger of ignition and explosion. The respective flash points of acetone, methyl ethyl ketone and alcohols are xe2x88x9218xc2x0 C., xe2x88x927xc2x0 C. and in the range of 12xc2x0 to 14xc2x0 C. Since those solvents are highly volatile, evaporate easily and have irritating smells, operators using those solvents need to wear personal protective equipment, such as a gas mask. Furthermore, those solvents are detrimental to health, and there are problems in working in an environment using those solvents.
Accordingly, it is an object of the present invention to obviate manual solvent cleaning work and to enable the automatic solvent cleaning of containers.
Another object of the present invention is to provide a container cleaning method capable of automatically carrying out a solvent cleaning process and a rinsing process.
A further object of the present invention is to provide a cleaning apparatus capable of automatically carrying out a container cleaning method comprising a solvent cleaning process and a rinsing process.
According to one aspect of the present invention, a container cleaning method uses a water-soluble or partially water-soluble solvent having a relatively high flash point of 55xc2x0 C. or above instead of a solvent having a low flash point. The container cleaning method comprises the steps of cleaning containers with a water-soluble or partially water-soluble solvent having a relatively high flash point of 55xc2x0 C. or above by jetting the solvent against the containers in a cleaning chamber formed in a solvent cleaning vessel, transferring the containers cleaned with the solvent to a rinsing chamber formed in a rinsing vessel, and jetting a rinsing liquid against the containers in the rinsing chamber.
According to another aspect of the present invention, a container cleaning apparatus comprises: a solvent cleaning unit having a solvent cleaning chamber internally provided with solvent jetting means for jetting a water-soluble or partially water-soluble solvent; a rinsing unit having a rinsing chamber connected to the solvent cleaning chamber and internally provided with rinsing liquid jetting means; a conveyor extended through the solvent cleaning chamber and the rinsing chamber; a container support device provided on the conveyor to be conveyed thereby for supporting containers thereon so that the containers can be cleaned with the water-soluble or partially water-soluble solvent jetted by the solvent jetting means and can be rinsed with the rinsing liquid jetted by the ringing liquid jetting means; and shutting devices having shutters capable of being moved between closed positions to close an entrance to the solvent cleaning chamber and to isolate the solvent cleaning chamber from the rinsing chamber, and open positions to permit the container support device and the containers supported on the container support device to move from the solvent cleaning chamber to the rinsing chamber.
The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings.